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From: Jason Gunthorpe <jgg@nvidia.com>
To: Gal Pressman <galpress@amazon.com>
Cc: Doug Ledford <dledford@redhat.com>, <linux-rdma@vger.kernel.org>,
	Alexander Matushevsky <matua@amazon.com>,
	Shadi Ammouri <sammouri@amazon.com>,
	Yossi Leybovich <sleybo@amazon.com>
Subject: Re: [PATCH for-next v4 3/4] RDMA/efa: User/kernel compatibility handshake mechanism
Date: Mon, 27 Jul 2020 15:56:33 -0300
Message-ID: <20200727185633.GA70218@nvidia.com> (raw)
In-Reply-To: <20200722140312.3651-4-galpress@amazon.com>

On Wed, Jul 22, 2020 at 05:03:11PM +0300, Gal Pressman wrote:
> Introduce a mechanism that performs an handshake between the userspace
> provider and kernel driver which verifies that the user supports all
> required features in order to operate correctly.
> 
> The handshake verifies the needed functionality by comparing the
> reported device caps and the provider caps. If the device reports a
> non-zero capability the appropriate comp mask is required from the
> userspace provider in order to allocate the context.
> 
> Reviewed-by: Shadi Ammouri <sammouri@amazon.com>
> Reviewed-by: Yossi Leybovich <sleybo@amazon.com>
> Signed-off-by: Gal Pressman <galpress@amazon.com>
>  drivers/infiniband/hw/efa/efa_verbs.c | 40 +++++++++++++++++++++++++++
>  include/uapi/rdma/efa-abi.h           | 10 +++++++
>  2 files changed, 50 insertions(+)
> 
> diff --git a/drivers/infiniband/hw/efa/efa_verbs.c b/drivers/infiniband/hw/efa/efa_verbs.c
> index 26102ab333b2..fda175836fb6 100644
> +++ b/drivers/infiniband/hw/efa/efa_verbs.c
> @@ -1501,11 +1501,39 @@ static int efa_dealloc_uar(struct efa_dev *dev, u16 uarn)
>  	return efa_com_dealloc_uar(&dev->edev, &params);
>  }
>  
> +#define EFA_CHECK_USER_COMP(_dev, _comp_mask, _attr, _mask, _attr_str) \
> +	(_attr_str = (!(_dev)->dev_attr._attr || ((_comp_mask) & (_mask))) ? \
> +		     NULL : #_attr)
> +
> +static int efa_user_comp_handshake(const struct ib_ucontext *ibucontext,
> +				   const struct efa_ibv_alloc_ucontext_cmd *cmd)
> +{
> +	struct efa_dev *dev = to_edev(ibucontext->device);
> +	char *attr_str;
> +
> +	if (EFA_CHECK_USER_COMP(dev, cmd->comp_mask, max_tx_batch,
> +				EFA_ALLOC_UCONTEXT_CMD_COMP_TX_BATCH, attr_str))
> +		goto err;
> +
> +	if (EFA_CHECK_USER_COMP(dev, cmd->comp_mask, min_sq_depth,
> +				EFA_ALLOC_UCONTEXT_CMD_COMP_MIN_SQ_WR,
> +				attr_str))
> +		goto err;

But this patch should be first, the kernel should never return a
non-zero value unless these input bits are set

Jason

  reply index

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-22 14:03 [PATCH for-next v4 0/4] Add support for 0xefa1 device Gal Pressman
2020-07-22 14:03 ` [PATCH for-next v4 1/4] RDMA/efa: Expose maximum TX doorbell batch Gal Pressman
2020-07-22 14:03 ` [PATCH for-next v4 2/4] RDMA/efa: Expose minimum SQ size Gal Pressman
2020-07-22 14:03 ` [PATCH for-next v4 3/4] RDMA/efa: User/kernel compatibility handshake mechanism Gal Pressman
2020-07-27 18:56   ` Jason Gunthorpe [this message]
2020-07-28 11:50     ` Gal Pressman
2020-07-28 12:28       ` Jason Gunthorpe
2020-07-28 13:07         ` Gal Pressman
2020-07-22 14:03 ` [PATCH for-next v4 4/4] RDMA/efa: Add EFA 0xefa1 PCI ID Gal Pressman
2020-07-29 12:28 ` [PATCH for-next v4 0/4] Add support for 0xefa1 device Jason Gunthorpe

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